Muffler



R. A. HEATH July 21,1964

MUFFLER Fiied June 9, 1961 2 Sheets-Sheet 1 INVENTOR. FoZerz fl .d 2

R. A. HEATH July 21, 1964 MUFFLER 2 Sheets-Sheet 2 Filed June 9, 1961 INVENTOR. F02 e7"? 17. Hedi/ United States Patent 3,141,518 MUFFLER Robert A. Heath, Jackson, Micln, assignor to Walker Manufacturing Company, a corporation of Delaware Filed June 9, 1961, Ser. No. 115,991 7 Claims. (Cl. 181-54) This invention relates to mufflers of the type used on automotive vehicles.

It is an object of this invention to provide a muffler design which incorporates satisfactory silencing in a small diameter casing.

It is also an object of this invention to provide a mufiler structure which can be produced very inexpensively and at the same time give satisfactory silencing.

It is also an object of this invention to provide a muffler construction which can be readily coated with a ceramic material in accordance with the procedures set forth in US. Patent No. 3,082,841.

It is also an object of this invention to provide a triflow type mufile-r utilizing a one-piece shell construction.

The invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a longitudinal cross-section through one embodiment of the invention as taken on line 1-1 of FIG. 2;

FIG. 2 is an end view taken from the left of FIG. 1;

FIG. 3 is a cross-section taken along the line 3-3 of FIG. 1;

FIG. 4 is a cross-section taken along the line 44 of FIG. 1;

FIG. 5 is a longitudinal section through another form of muffler, being a cross-section along the line 5--5 of FIG. 7;

FIG. 6 is an end view taken from the left of FIG. 5;

FIG. 7 is a crosssection along the line 77 of FIG. 5; and

FIG. 8 is a cross-section along the line 88 of FIG. 5.

The muffler 1 of FIGS. l4 has an outer one-piece steel tube casing 2, preferably 4 inches in diameter, which is round in cross-section and which has the ends swaged down to provide an integral inlet 3 and integral outlet 5.

The inlet bushing 3 is preferably about half the diameter of and connected to the ends of the main. body and maximum diameter section 7 of the casing 2 by means of the outwardly tapering section 9 and the outlet end of the body portion 7 of the casing is connected by a converging section 11 to the outlet bushing 5. As indicated in FIG. 1 and FIG. 2, the bushings 3 and 5 are substantially parallel to each other but are offset transversely so that the muffler casing section 7 extends at an angle to both. This arrangement enables the mufller to lit in the space allocated for it in a given automotive application.

Inside of the casing 2 of the muffler at the ends of the section 7 are transverse partitions 13 and 15 which are spotwelded by means of their peripheral flanges to the wall of the casing. Also, spotwelded to the walls of the casing are two additional partitions 17 and 19. The partitions divide the interior of the muffler easing into a series of chambers 21, 23, and 25 in addition to the inlet chamber 27 formed by the tapered section 9 and the outlet chamber 29 formed by the tapered section 11.

The four partitions have flanged openings to support three tubes inside of the casing. The first of these is an inlet tube 31 which contains louvers along most of its length and around its periphery. The inlet tube 31 is offset from the center line of the mufiler cross-section as can be seen in FIG. 3 and also in FIG. 1. it terminates up- 3,141,5l8 Patented July 21, 1964 stream from the partition 17 so that gases flowing through the entire length of the tube 31 will empty into the chamber 21. The inlet tube 31 engages and is spotwelded at 33 to the periphery of an outlet tube 35 which, like the tube 31, extends through and is spotwelded in flanged openings in the partitions 15, 17, and 19 through which it passes. The tube 35 is also offset in two directions from the center line of the muffler casing as can be seen best in FIG. 3 as well as in FIG. 1. The inlet end of the outlet tube 35 is located in the chamber 21 and is spaced downstream from the inlet end partition 13. The portion of the tube 35 with the chamber 21 and the chamber 23 is provided with louvers but that portion within the chamber 25 is imperforate. A restrictor device 37 is spotwelded in the inlet end of the tube 35 to provide a reduction in diameter followed by an abrupt enlargement of diameter in the gas passage.

An imperforate tuning tube 39 is supported in flanged openings in the partitions 17 and 13 in a position offset from the center line of the casing and somewhat closer to the wall of the casing than are the louver tubes 31 and 35. The tube 39 forms the: only inlet and outlet to the chamber 25 which therefore constitutes a tuning chamber.

Gases entering the mufiier 1 through the line 3 will be subject to the silencing action of an expansion as they ass into the chamber 27. Passing through the louvered inlet tube 31 they will empty into chamber 21 and reverse their direction of flow to flow back toward the inlet end until they encounter partiion 13 whereupon he direction of flow will be reversed again to enter the tube 35 through the restrictor 37 and then pass out into the chamber 29 and subjected to the restricting action thereof to pass into the outlet bushing 5. The combination of louvers in tubes 31 and 35 and the chamber 21 will attenuate some of the medium and high frequencies and permit lay-passing between the two tubes while the chamber 23 will act as a high frequency attenuating spit chamber. The tuning tube 39 and chamber 25 will act as a tuning chamber to attenuate low frequencies. Thus, it will be seen that the gas, in passing through the .mufiler 1, will be subjected to several abrupt changes in diameter, to the action of spit chambers and tuning chambers, thus enabling it to effectively attentuate a wide range of frequencies of sound.

The foregoing is accomplished in a very compact small diameter design which may be rather inexpensively manufactured.

This design also is well adapted to be ceramic coated by a dip process as described in the aforementioned U.S. PatentNo. 3,082,841. For this purpose, each of the internal partitions 13, 17, 19 and 15 have a pair of dia metrically opposed drainage openings 41 therein which are located in the same plane as the hook hole 43 by which the mufiler will be suspended when it is immersed in the ceramic and the various other liquids involved in the ceramic coating process. These holes will enable the gases to be ventilated and the liquids to drain out through the outlet opening 5 when the buflier is suspended from the inlet end by means of the hole 43.

FIGS. 5-8 illustrate a mufiier 101 which is even less expensive to manufacture than the mufller 1 but which omits the tuning chamber. Thus, in applications Where very low frequencies are not encountered, the muffler 101 may be satisfactorily employed as it will be effective to handle the higher and the medium frequencies.

The mufiler 101 has a casing 103 which is provided with an inlet 105 and an outlet 107, all of which are integral with the casing and preferably formed from a steel tube (preferably 4 inches in diameter). Only two partitions are used in the muffler 101, thus greatly reducing its cost. These are the inlet end partition 109 and the outlet partition 111. These partitions, along with the tapered end portions 113 and 115 of the mulfier casing, divide the interior of the casing into chambers 117, 119 and 121. The partitions 109 and 111 along with a portion 123 of the outlet bushing 107 serve to support a pair of louver tubes 125 and 127, each of which is louvered along substantially its entire length. These louver tubes are formed from originally fiat material which is lock-seamed, as indicated at 129. However, instead of being formed into circular cross-section they are formed into substantially triangular cross-section along a substantial portion of their length and such triangular sections are in contact, face to face, and spotwelded as seen in FIG. 7. The portions of the tubes 125 and 127 which extend in or through the partitions are circular as seen at 131, 135, and 137. The outlet end of the tube 125 is shaped to form a pair of reduced size outlet openings 139 by forming the center section of the tube so that it contacts the bottom section as indicated in FIGS. 7 and 8'. This reduction in cross-sectional area of the outlet of tube 125 provides a restrictor for added silencing effect.

Gases entering the mufiier 101 pass through the inlet bushing 105 and enter an expansion chamber 117. They flow from this chamber into the tube 125 and encounter a change in cross-section particularly as they pass through the dual outlets 139 and enter the return flow chamber 119. In this chamber they reverse their direction of flow twice and flow back through the outlet tube 127 to the outlet bushing 107. While passing through the tubes 127 and 125 the gases are subjected to the silencing action afforded by the louvers in both tubes, these also permitting some cross breeding. The tube 127 is louvered in the chamber 121 to provide a spit chamber action to attenuate high frequencies.

The partitions 109 and 111 have ventilation and drainage holes 141 located on opposite sides and in a corn mon plane with a hook or suspension hole 143 formed in the outlet bushing 107. The muffler will be sus ended by means of hole 143 when it is ceramic coated in accordance with the procedure described in US. Patent No. 3,082,841 and the holes 141 will provide for ventilation and drainage during this process.

Throughout the drawings the small x markings indicate spotwelds.

It will noW be realized that the invention provides a small, compact mufiler containing various silencing components that may be inexpensively manufactured and which is also well adapted for a ceramic coating treatment. Modifications from the specific structure shown are within the spirit and scope of the invention.

I claim:

1. In a muffler, a casing having a body portion of maximum width and tapered end portions at opposite ends of the body portion and an inlet and an outlet bushing connected respectively to the ends of the tapered portions, four spaced partitions located in the body portion of the casing and providing in downstream order a tri-flow chamber located between the first and second of the four partitions, a spit chamber located between the second and third of said partitions, and a tuning chamber located between the third and fourth of said partitions, an inlet tube supported in the first partition and terminating upstream of the second partition and being louvered in the tri-fiow chamber, an outlet tube extending through the last three partitions and emptying into the tapered section of the casing adjacent the outlet bushing, said outlet tube being louvered in the tri-fiow chamber and in the spit chamber, a tuning tube supported in the second and third partitions and extending into the tuning chamber and forming the only inlet and outlet of the tuning chamber, said inlet tube and outlet tube being in engagement with each other and spotwelded together, said inlet tube being out of alignment with the inlet bushing, the inlet of the outlet tube being located in the triflow chamber and downstream from the first partition, said tri-fiow chamber comprising means for silencing medium and high frequencies, said spit chamber comprising means for silencing high frequencies, and said tuning chamber comprising means for silencing low frequencies, the space in said casing being said inlet bushing and said first partition comprising an unobstructed inlet chamber having the inlet tube as its outlet, and the space in said casing between the fourth partition and the outlet bushing comprising an unobstructed outlet chamber having the outlet tube as its inlet.

2. The invention set forth in claim 1 including a restrictor formed in the inlet end of one of the inlet and outlet tubes.

3. The invention set forth in claim 1 wherein the casing is round in cross-section and said inlet bushing is approximately one-half of the diameter of the casing.

4. The invention set forth in claim 3 wherein the inlet tube and the outlet tube and the tuning tube are all completely out of alignment with each other but approximately half of the cross-sectional area of each is in alignment with the inlet bushing.

5. A mufiler comprising a tubular casing of round cross-section having reduced end portions terminating in inlet and outlet bushings, a pair of spaced partitions supported inside the casing, a pair of overlapping tubes in a chamber between the two partitions, each of said tubes being circular in cross-section at end portions thereof and said end portions extending in and spotwelded to flanged openings in the partitions, the remainder of said tubes being louvered and triangular in cross-section and sides of the triangles on the two tubes being in engagement with each other and spotwelded together, the end of one of the tubes being supported in one of the bushings, and one of said tubes being louvered in the space between a partition and the end of the casing to form a spit chamber.

6. A compact mufiler comprising a round tubular casing, the inlet end of said casing being tapered to form a conical inlet chamber, an inlet bushing opening into the small end of said tapered portion, an inlet partition located at the inlet end of the casing and an outlet partition located at the outlet end of the casing, an inlet tube supported in the inlet partition and an outlet tube supported in the outlet partition, said tubes overlapping and being spotwelded together to mutually support each other, each of said tubes being louvered and each of said tubes opening into a common chamber, said louvers providing for cross-bleeding and for silencing in said chamber, the opening of one of said tubes into said common chamber being provided with restrictor means to decrease the cross-sectional area of the opening, said inlet and outlet tubes being formed over substantially the major portion of their lengths in a triangular cross-section, sides of the triangular portions of the inlet and outlet tubes being in engagement with each other and spotwelded to each other over a large portion of the lengths of each of the tubes.

7. A compact mufiier comprising a round tubular casing, the inlet end of said casing being tapered to form a conical inlet chamber, an inlet bushing opening into the small end of said tapered portion, an inlet partition located at the inlet end of the casing and an outlet partition located at the outlet end of the casing, an inlet tube supported in the inlet partition and an outlet tube supported in the outlet partition, said tubes overlapping and being spotwelded together to mutually support each other, each of said tubes being louvered and each of said tubes opening into a common chamber, said louvers providing for cross-bleeding and for silencing in said chamber, the opening of one of said tubes into said common chamber being provided with restrictor means to decrease the crosssectional area of the opening, the end 016m of the tubes in said common chamber being bifurcated so as to form 5 6 two ouilet openings out of the common cross-section of 2,166,417 Manning July 18, 1939 the tube. 2,618,354 Hedrick Nov. 18, 1952 2,825,421 Bryant Mar. 4, 1958 References Cited in the file of th1s patent 2,372,998 Tinker Feb. 10, 1959 UNITED STATES PATENTS 5 1,860,146 Gray May 24, 1932 FOREIGN PATENTS 2,138,477 Ludlow Nov. 29, 1938 624,199 France Mar. 29, 1927 

1. IN A MUFFLER, A CASING HAVING A BODY PORTION OF MAXIMUM WIDTH AND TAPERED END PORTIONS AT OPPOSITE ENDS OF THE BODY PORTION AND AN INLET AND AN OUTLET BUSHING CONNECTED RESPECTIVELY TO THE ENDS OF THE TAPERED PORTIONS, FOUR SPACED PARTITIONS LOCATED IN THE BODY PORTION OF THE CASING AND PROVIDING IN DOWNSTREAM ORDER A TRI-FLOW CHAMBER LOCATED BETWEEN THE FIRST AND SECOND OF THE FOUR PARTITIONS, A SPIT CHAMBER LOCATED BETWEEN THE SECOND AND THIRD OF SAID PARTITIONS, AND A TUNING CHAMBER LOCATED BETWEEN THE THIRD AND FOURTH OF SAID PARTITIONS, AN INLET TUBE SUPPORTED IN THE FIRST PARTITION AND TERMINATING UPSTREAM OF THE SECOND PARTITION AND BEING LOUVERED IN THE TRI-FLOW CHAMBER, AN OUTLET TUBE EXTENDING THROUGH THE LAST THREE PARTITIONS AND EMPTYING INTO THE TAPERED SECTION OF THE CASING ADJACENT THE OUTLET BUSHING, SAID OUTLET TUBE BEING LOUVERED IN THE TRI-FLOW CHAMBER AND IN THE SPIT CHAMBER, A TUNING TUBE SUPPORTED IN THE SECOND AND THIRD PARTITIONS AND EXTENDING INTO THE TUNING CHAMBER AND FORMING THE ONLY INLET AND OUTLET OF THE TUNING CHAMBER, SAID INLET TUBE AND OUTLET TUBE BEING IN ENGAGEMENT WITH EACH OTHER AND SPOTWELDED TOGETHER, SAID INLET TUBE BEING OUT OF ALIGNMENT WITH THE INLET BUSHING, THE INLET OF THE OUTLET TUBE BEING LOCATED IN THE TRIFLOW CHAMBER AND DOWNSTREAM FROM THE FIRST PARTITION, SAID TRI-FLOW CHAMBER COMPRISING MEANS FOR SILENCING MEDIUM AND HIGH FREQUENCIES, SAID SPIT CHAMBER COMPRISING MEANS FOR SILENCING HIGH FREQUENCIES, AND SAID TUNING CHAMBER COMPRISING MEANS FOR SILENCING LOW FREQUENCIES, THE SPACE IN SAID CASING BEING SAID INLET BUSHING AND SAID FIRST PARTITION COMPRISING AN UNOBSTRUCTED INLET CHAMBER HAVING THE INLET TUBE AS ITS OUTLET, AND THE SPACE IN SAID CASING BETWEEN THE FOURTH PARTITION AND THE OUTLET BUSHING COMPRISING AN UNOBSTRUCTED OUTLET CHAMBER HAVING THE OUTLET TUBE AS ITS INLET. 